Centrifugal separator



July 3, 1934. G KNOPP 1,964,992

CENTRIFUGAL SEPARATOR Filed Aug. 27, 1929 6 Sheets-Sheet l O O 7 )1 )1 I nnnunnnnnnun' y 3, 1934. e. KNOPP CENTRIFUGAL SEPARATOR Filed Aug. 27, 1929 6 Sheets-Sheet 2 7 117 Lm mam.

July 3; 1934.

G. KNOPP 1,964,992

CENTRIFUGAL SEPARATOR Filed Aug. 27, 1929 6 Sheets-Sheet 3 .772 21812 for y 3, 1934. G, KNOPP 1,964,992

CENTRIFUGAL SEPARATOR Filed Aug. 27. 1929 6 Sheets-Sheet 4 Invenfor JUHY 3, 1934. KNOPP CENTRIFUGAL SEPARATOR Filed A1121. 2?, 1929 6 Sheets-Sheet 5 Patented Jul-1y 3, @3 1 patent ori signer to fl'ientriiugal Engineering and Patents Corporation, Jersey City, N. 3., a corporation oil New Jersey Application August 27, 192%), Serial No. 385.7% lln Germany August 12, 1925 3% Claims.

My present invention relates to a centrifugal separator for removing impurities from paper --pulp or other fibrous material in which separator the paper pulp accumulates within a rotating drum by means of centrifugal action in vertical layers upon the wall of the drum and is discharged over the top edge of the drum. By means of rings secured to the wall of the drum the coarse or heavier particles are separated and by means of a ring located at the top edge of the drum the fine or lighter particles are sepa rated so that only perfectly pure and uniform paper pulp is discharged at the top of the drum.

The main object of the invention is to con= struct a separator'brsimple and appropriate construction which may be manufactured at low costs and which is entirely reliable when working. Another object of my invention is to arrange a plurality of separators in such a manner as to render a continuous working possible while one or some or these separators forming a unit are shut down.

These and other objects of my invention will become more readily apparent upon a study ofthe following specification when read in connection with the accompanying drawings and ap pended claims.

In the drawings, Fig. 1 shows one example of a separator in elevation, partly in section. The section is made through'the axis of rotation 02 the drum; the paper pulp is admitted to the separator from above concentrically to the axis.

Fig. 2 is a similar view of a separator constructed in another manner. The admission of the paper pulp is from below concentrically to the axis'of thadrum. 1 K Fig. 3 is an elevation (partly in section) oi a third mode or construction oi a separator in which the paper pulp is admitted from the top at one side of the drum only. 4

Fig. a shows another form of construction of the separating drum, the outside periphery, of

' this drum being cylindrical. I

the common cas'ng for the group of separators.

Fig. 8 is a section taken on line. VIIIVIII of Fi 7.

(or. ass-tel Fig. 9 is a section taken on line EZ-fi oi Fig. '7.

Fig. 10 shows another arrangement of a group of separators differing from that shown in Figs. 5 and 5.

Fig. 11 shows a further modification oi the separating drum.

The centrifugal separator comprises a 15 which is mounted vertically in a casing and which may be driven in any desired manner, for example by a belt or the like. In the construc= tion shown in Figs. 1-3 the drum is driven by an electric motor 16 arranged .above the drum and connected with it by means of a shaft 17 directly or through an intermediate gear (not shown). m The drum 15 is provided with a bottom 18 having openings 19 which may be closed by flaps 20. The openings 19 and the flaps 20 are provided in order to render possible an easy and simple cleaning of drum 15, which is efiected by a. water jet 5 or the like. The impurities which are collected at the bottom 18 when cleaning the drum 15, are discharged through the openings 19 together with the water used for cleaning. When the sens rator is working the openings 19 remain closed. 569 The drum 15 is secured with its bottom ieto the shaft 1'7 the ends of which run in bearings 21 and 21' (Figs. 1 and 2).

The shaft 17 may however run in a hanging bearing 22 so that drum 15 is freely suspended from the cover 23 (Fig. 3).

The pulp is supplied through a feed or admis sion pipe 24 which is connected, according to Fig. 1, above the drum to a pipe 25, concentrically arranged around the shaft 17. The paper pulp 26 w flows through said pipe 25 down to the bottom. 18 of drum 15. At the discharge end of pipe 25 deflecting means or plates 2'7 deflect the paper pulp in a radial direction against the wall of drum 15. Q5

As shown in Fig. 2 the supply or admission pipe 24' for the pulp 26 may also be located at the bottom of the drum. This arrangement has the advantage of simplifying the connection between the drum 15 and the shaft 17. The pulp enters the drum in this case in an ascending flow and is deflected bydeflecting plates 2'7 horizontally and radially againstlghe inner wall of the drum where it forms a series of substantially cylindrical pools against the wall of the drum.

It is of advantage when admitting the pulp con centrically with relation to shaft 17, to arrange the pipe 25 in such a manner that it is caused to rotate together with the drum so that already in this pipe the pulp is caused to rotate likewise.

In this case the pulp, when entering the drum from the pipe 25, is very uniformly distributed into the drum.

In the form of construction shown in Fig. 3 the pulp is supplied likewise from the top of drum. Here however the supply or admission pipe 24" is arranged in such a manner and connected to a pipe 28, that the pulp is supplied to the inside of the drum on one side only or eccentrically.

The drum 15 is provided as shown in Figs. 1 to 3 with steps or sections 29 on which rings 30 are provided over which the pulp is discharged from the chamber below a ring 30 to the next chamber above that ring.

According to Fig. 4 the drum is formed cylindrically and in this case rings 31 of angle iron are secured to the inside of the drum, the inner diameter of said rings becoming greater the higher said rings are located.

The effect of the arrangement of the steps or sections upon the pulp lies in the fact that the pulp is vibrated in such a manner, when being thrown over the top edge of one step into the next higher chamber, that the finer impurities associated with the fibres are released and separated. The pulp thus treated is delivered by the centrifugal action only without special auxiliary' means from one drum section or chamber to the next higher section or chamber of the drum. The number of drum steps or sections used depends upon the working conditions as for instance upon the percentage and the nature of the im purities contained in the pulp, further upon the desired quality of the purified material etc.

At the upper end of the drum 15 an annular rim 32 is provided, this rim projecting radially inward and outward from the wall of the drum and having at its inner edge a downwardly turned flange 33. Below this flange a skimming ring 34 is adjustably mounted. This ring is annular in shape, the inner edge being substantially inward of the flange 33, the outer edge of the ring 34 being substantially outward of the flange 33. From the outer edge of the ring 34 a flange 35 of substantial width extends downwardly, this flange being inwardly spaced from and parallel to the upper portion 350 of the wall of the drum 15. The skimming ring 34 is vertically adjustable so that the clearance between its upper face and the lower edge of the flange 33 may be adjusted at will. By this means, the depth of the pool of pulp stock below the rim 32 may be regulated if the rate of supply of pulp stock into the drum is maintained substantially constant. Immediately below the portf on 350 of the drum wall, the inner surface of the wall is conical, converging downwardly and inwardly as at 351, this conical portion terminating in the crest 352 of a rib 353. The diameter of the crest 352 is preferably greater than the diameter of the flange 33, so that the rib 353 is at all times well submerged in the pool of stock maintained below the rim 32.

The stream of pulp stock which is supplied to the lower end of the drum forms a pool below the rib 30. Within this pool, a gradually consolidating mat of pulp fibers is formed over which.

the incoming stream of pulp flows upwardly within the drum in the form of a thin cylindrical sheet. This stream is combed by the surface fibers in the mat below the rib 30, the action being to separate from the stream and retain the foreign particles of greater density, which are brought by the stream. The stream then flows over the sharp crest of the rib 30 which tends to break up the fiber clumps and to separate the tion also tending to separate from the fibers any additional particles of dirt or foreign matter which have been caught in such clumps of fiber. A second mat of fiber is formed between the rib 30 and the rib 353. This mat also combs the stream of stock and removes therefrom any foreign matter of greater density than the pulp which may have escaped the lower mat. Since the crest 352 of the rib 353 is well submerged beneath the,surface of the upper pool, the pulp stream flows over this crest with little surface disturbance. Instead of an abrupt outward drop above the crest 352, a gentle outward slope is provided by the inner surface of the drum wall which diverges upwardly so that eddy currents at this point, which might disturb the surface of the pool, are avoided. Thus foreign particles of lesser density than that of the pulp are carried undisturbed on the surface of the stream and are collected in the pocket formed by the skimming ring 34 and its flange 35. The purified pulp stream fiows in the passage between the flange 35 and the drum wall portion 350, the space between these two members being such that little or no mat is formed. The stream then is forced by displacement through the narrow clearance between the upper face of the skimming ring 34 and the lower edge of the flange 33. The stock then is discharged outwardly over the upper face of the rim 32 and is collected in a suitable trough 36 which surrounds the upper end of the drum and is preferably beneath the cover 23.

Due to the rapid rotation of the drum 15, which may be of the order of 500 or more revolutions perminute, the stock which is discharged over the rim 32 at the upper end of the drum is flung radially, outward with considerable violence. Hence there is unavoidable splashing and turbulence in the trough 36. In order to prevent loss of stock between the drum and the trough 36,

a suitable splash guard may be provided. As shown, the trough 36 has'a horizontal shelf 37 extending downwardly therefrom toward the drum, this shelf terminating in an upwardly projecting flange 370. The rim 32 has at its outer edge a downwardly projecting flange 38 which overlaps the flange 3'70, and thus prevents the escape of stock over the inner edge of the trough 36. If desired, the outwardly flung stream of stock may be caught and deflected downwardly by a fixed ring 40 which may be supported from the cover 23 and may have a downwardly diverging wall horizontally alined with the rim 32. This breaks the velocity of the stock leaving the rim 32. If desired, the ring 40 may be arranged so that its lower edge 41 is situated above the channel 36 proper and not above the horizontal portion 37 of such channel as shown on the drawing. The stock which is collected in the trough 36 may be discharged therefrom as through a suitable pipe connection 39.

-In order to render possible a continuous working and especially a continuous flow of the paper pulp to the paper making machine, a plurality 1 of drums or separators may be arranged and connected to a common admission pipe and, discharge pipe, respectively. In the arrangement shown in Figs. 5-9 four drums a, b, c, d are arranged symmetrically around a com mon casing or collector and distributor box. This box has two compartments, the lower compartment being adapted to collect refined pulp stock from the several centrifuges and to forward such stock through a single discharge duct idto a paper-making machine or elsewhere as desired. The upper compartment receives stock to be purified, such stock being delivered thereto through a supply duct 43, and distributed to the several centrifuges through suitable ducts 46. While four centrifuges are illustrated as served by a single collector box, it is obvious that a greater or lesser number may be similarly con-- nected to the box.

While the collector box is susceptible to various forms and arrangements, in the embodiment illustrated on the drawings the lower compartment 42 has an enlarged lower portion 421 into which connecting pipes 49 open tangentially. These pipes bring the refined pulp from the several centrifuges to the collectorbox. The upper part of the compartment 42 is reduced in diameter forming a neck 422 which terminates in an open mouth 423. Through this mouth escapes the air which is entrained with the pulpstock in the centrifuges and which is carried into the collector box with the pulp streams. A substantial portion of this air is mixed with the stock in the form of foam. The tangential entrance of the streams into the compartment 42 maintains a vortex therein which is joined by the streams with minimum turbulence. This facilitates the separation of the foam from the body of the stock stream. A spray nozzle 58 is provided to project a continuous spray downwardly on the surface of the pool within the compartrnent 42 so as to break up the bubbles thereon and destroy the foam. A spray ring 51 may also be mounted adjacent to the wall of the compartto wash the wall and prevent the accumulation of pulp fibers thereon.

The lower portion of the casing is constricted and projects downwardly in the form of a neck 52 which extends deeply into a basin 520 communicating with the discharge duct as. This structure forms a foam trap and results in the delivery of foam-free refined pulp stock to the discharge duct is.

As shown, the distributing compartment 45 may be in the form of a ring encircling the neck e22. construction of the box as a whole. In order to equalize the distribution of pulp to the several centrifuges, a bafiie or damming wall l? is provided within the compartment 45 concentric with the neck 422, and mounted with clearance below its lower edge. Froin'the floor oi the casing a circular weir or second baffle 48 rises upwardly, this baifie being concentric with and radially outside of the wall 47. Thus in order to reach the several connecting pipes 46, the pulp entering the compartment 45 must flow under the wall 4'"! and must spill over the weir 48. This ensures uniform distribution to the pipes as and also tends break up fiber clumps by resulting agitation of the stock.

The pipes 46 leading from the casing 42 to different drums may be closed each independently of the others so that any one of the may be shut down for cleaning purposes. the disconnection of one or the drums the other drums are supplied with the excess of the pulp. A drum may be disconnected every 10 to 12 hours for 20 to 30 minutes. This time depends of course upon the percentage of impurities contained in the pulp and may differ from 8 to 48 hours. It is preferable, when working continuously, to stop one of the drumsfor cleaning purposes alternately all the time as otherwise the other drums would be overcharge This results in a compact and convenient exchangeable.

having different widths and to obtain layers of If desired, fresh water may be introduced into the casing 42 which is mixed with the other water contained therein on account 01 the vortex created by the tangential arrangement of the pipes.

The casing may be provided with water sealed discharge openings preventing foam from being carried along by the pulp and delivered into the paper making machine. 7

The casing 42 is formed without pockets or the like in which lumps of fibres could accumulate. The paths of travel of the pulp are short and compact so that it is not necessary to often clean the casing and the partsconnected to it.

The construction or arrangement of Fig. 10 shows four drums or separators e, f, g, h ar ranged between a common admission or supply pipe 53 and a common discharge pipe 54. It will be possible (as is indicated to the right in Fig. 10) to connect further drums or separators i, k, m, n, to pipe 54: Further drums (not shown) might be connected to the admission pipe 53, if desired.

By the use of a separator constructed according to the invention the waste of the fiber is diminished by more than 50% because fibres which are interconnected with each other are separated when the pulp stream fiows over the crest of the rib and also by the impact of'the pulp'which is flung from the rim 32 of the drum against the ring 40 or a side of the trough 36 so that they are unfelted or unravelled. Further by the separation or the bunches of fibres the strength of the paper is increased and a perfect quality of paper is obtained as regards purity and transparency. Further with a separator constructed in accordance to the invention substantially no pulp is wasted as is the case in machines hitherto known for that purpose. The effect of the employment of a closed drum is that no loading or weighting material is lost when the pulp layer has been formed. For then only the heavy impurities of the pulp and of the weighting material (as for example, such impurities as sand or the like) are separated. The weighting material is therefore, according to the invention purified at the same time as the pulp. The rings 30 provided between the steps or sections 29 of the drum may preferably be made It thus is possible to use rings pulp of different thickness.

One form of construction is shown in Fig. ll. where a ring 30 is fastened to the ring so of the drum 15. This ring 30 may be replaced by others of different widths so that layers of pulp b,

b, b" of difierent thickness may be obtained.

Having thus described my invention, what I now claim as new and desire to secure by Letters Patent of the United States is as follows:

i. A centrifugal separator comprising a drum,

an outer closing ring located in the upper part of said drum and having an inner edge depending downwardly, an inner ring located below said edge to form a slot, and means for regulating the width or said slot to throttle the delivery or the material.

2. A centrilugal separator comprising a drum, an outer closing ring located in the upper part of said drum and having an inner edge depend ing downwardly; an inner ring located below said edge to form a slot, means for'regulatingthe width of said slot, and a projection on said inner ring depending downwardly into the material.

3. A centrifugal separator comprising a drum, a channel located around the top edge of said drum, the inner edge of said channel being extended substantially horizontally, an outer closing ring located in the upper part of said drum and having an inner edge depending downwardly to work together with said inner horizontal edge of said channel.

a. A centrifugal separator comprising a drum,

a channel located around the top edge of said drum to receive the material discharged therefrom, said channel having an inner edge extended horizontally from its main part, and a stationary ring located above said drum and having a lower edge, said lower edge located directly above said horizontal inner edge of said channel.

5. A centrifugal separator comprising a drum, a channel located around the top edge of said drum to receive the material discharged therefrom, and a stationary ring located above said drum and having a lower edge, said lower edge extending into said channel.

6. In combination with a plurality of centrifugal separators, an admission pipe common for all the separators, a common discharge pipe, a collector box connected both to said admission pipe and said discharge pipe, an annular space within said collector box, and connection pipes leading from said annular space to the difierent separators.

7. In combination with a plurality of centrifugal separators arranged to have a common admission pipe and a common discharge pipe, a collector box connected both to said admission pipe and said discharge pipe, an annular space within said collector box, connection pipes leading from said annular space to the different separators, an annular damming device, and an annular overfall-weir arranged in said annular space for uniformly distributing the material into the connection pipes.

8. In combination with a plurality of centrifugal separators arranged to have a common admission pipe and a common discharge pipe, a casing having two separate compartments connected respectively to said admission pipe and said discharge pipe, pipes each connected with one end to one of the separators, the other ends of said pipes connected to said casing.

9. In combination with a plurality of contrifugal separators arranged to have a common admission pipe and a common discharge pipe, a casing connected both to said admission pipe and said discharge pipe, and spraying means located in said casing to prevent the forming of lumps and to precipitate foam.

10. In combination with a plurality of centrifugal separators arranged to have a common admission pipe and a common discharge pipe, a casing connected both to said admission pipe and said discharge pipe, and a damming device located within said casing and interposed in the path of material passing to said separators;

11. In combination with a plurality of centrifugal separators arranged to have a common admission pipe and a common discharge pipe, and a casing connected both to said admission pipe and said discharge pipe the upper portion of said casing extending into said admission pipe thus forming an annular space.

12. A centrifugal separator comprising a rotatably mounted drum, driving means for said drum, rings secured to the inner wall of said drum one above the other and dividing said drum into sections, and further rings fastened to said first rings, respectively, for determining the thickness of the layers of pulp.

13. In a centrifugal separator for pulp stock,

eeaeoa a rotatable drum into which pulp stool: is fed, a pulp-receiving channel around said drum at the top thereof, a cover member for said drum and channel, a vertical drum-rotating shaft disposed axiallyof said drum and channel, and a motor carried by said covermember for rotating said shaft. 14. In a centrifugal separator for pulp stock, a rotatable drum, a driving shaft for said drum and extending axially therethrough, bearings for said drive shaft disposed above and below said drum, means for supplying pulp stool; to said drum concentrically with respect to said shaft, and a motor having its armature directly connected to one end of said shaft for rotating the same. v 15. In a centrifugal separator for pulp stock, a rotatable drum, 2. driving shaft for said drum and extending axially therethrough, bearings for said drive shaft disposed above and below said drum, and a pipe disposed around said shaft, said pipe defining a passage through which pulp stool; is fed to said drum.

16. In a centrifugal separator for pulp stock, a rotatable drum, 2. driving shaft for said drum and extending axially therethrough, bearings for said drive shaft disposed above and below said drum, and a pipe extending axially through said drum and disposed around said shaft, said pipe defining a passage through which pulp stock is fed to said drum.

17. A centrifugal separator comprising a drum, an outer closing ring located in the upper part of said drum and having an inner depending edge, an inner ring located below said edge to form a slot, and means for vertically adjusting said inner ring to thereby vary the width of said slot and throttle the delivery of the material.

18. In a centrifugal separator for pulp stock,

-a rotatable drum along which the pulp stock travels upwardly, a channel around said drum for receiving the pulp stock therefrom, said channel having a ledge extending toward said drum, and a deflector member disposed above said drum and ledge and sloping toward the latter, the lower surface of said deflector member being spaced from said-ledge.

19. The combination with a centrifugal separator for pulp stock, of a collector box, and a plurality of conduits connecting said separator and collector box, pulp stock passing from said collector box to said separator through one of said conduits, pulp stock passing from said separator to said collector box through another of said conduits.

20. The combination with a plurality of centrifugal separators for pulp stock and rotatable only about their respective longitudinal axes, of

a collector b'ox, conduits leading from the rethe stock within the casing regardless of the rate I of supply of stock thereto.

eeaeea 22. A collector box for use with pulp stock refiners comprising a casing opening upwardly and having a radially enlarged intermediate portion, a plurality of pipes leading tangentially into said intermediate portion, and a foam trap at the bottom of the casing through which the collected stock may be discharged, said trap including means for discharging stock downwardly from the lower portion of the casing, then upwardly to a sufficient level to maintain a min-- imum surface level for the stock within the casing regardless of the rate of supply of stock thereto.

23. A collector box for use with pulp stock refiners, comprising a casing opening upwardly and having a radially enlarged intermediate portion, a plurality of pipes leading tangentially into said intermediate portion, means for projecting spray within said casing to destroy foam therein, and a foam trap in the bottom of said casing through which the collected stock may be discharged.

24. Apparatus for distributing pulp stock, comprising a casing, means for supplying a stream of stock to said casing, a plurality of ducts leading from said casing, and means for automatically distributing the supply of stock uniformly between the several ducts, said distributing means including a plurality of concentric baflies within said casing.

25. A collector and distributor box for use with pulp stock refiners, comprisinga casing having a central compartment opening upwardly and having a. reduced upper portion and a radially enlarged portion below said upper portion, a plurality of pipes leading into said enlarged portion, and a foam trap in the bottom of said casing through which collected stock may be discharged, said casing also having an annular compartment surrounding said reduced upper portion of the central compartment, a supply duct leading into said annular compartment, 9. plurality of connecting ducts leading from said annular compartment, and means for automatically distributing the flow from said supply duct uniformly between said connecting ducts.

26. A centrifugal separator for pulp stock, comprising a drum rotatableon a vertical axis, means for introducing stock into said drum hear its lower end, an inwardly extending rim on the upper end of said drum having an inner flange extending downwardly, an annular skimming ring below said flange and adjacent thereto, said ring having a flange extending downwardly from its outer edge substantially concentric with and adjacent to the upper portion of the drum wall, and means for collecting stock discharged over the rim of the drum.

27. A centrifugal separator for pulp stock, com-= prising a drum rotatable on a vertical axis, means for supplying a stream of stock to the lower end of the drum, an upwardly extending rim at the upper end of the drum having an lnnerfiange extending downwardly, an annular skimming ring mounted below said flange, said flange being adjacent to an intermediate portion of said ring between the inner and outer edges thereof, a downwardly extending flange on the outer edge of said ring, and means for adjusting the clearance between the ring and the flange of the rim.

28. A centrifugal separator for pulp stock, comprising a drum rotatable on a vertical axis, an inwardly projecting annular rib on the inner surface of said drum between the upper and lower ends thereof below which rib a pool of stock may be maintained during the operation of the drum, an inwardly projecting annular rim at the upper end of the drum below which a second pool may be maintained, an intermediate annular rib normally submerged in said second pool, the inner surface of the drum immediately above the crest of said intermediate rib flaring upwardly and outwardly to its greatest diameter, and a skimming ring below and adjacent to said rim, the outer edge of said skimming ring being normally submerged in said second pool.

29. A centrifugal separator for pulp stock, comprising a drum rotatable on a vertical axis, means for supplying stock to the lower end of the drum, an annular rib projecting inwardly from the wall of the drum between the upper and lower ends thereof below which a pool of stock may be maintained during the operation of the drum, an inwardly extending rim on the upper end of the drum below which a. second pool maybe maintained, said rim having its inner edge turned downwardly, ,an annular skimming ring below and adjacent to said edge, and a flange of subprising a drum rotatable on a vertical axis, means for supplying stock to the lower end of said drum, an annular rib projecting inwardly from the wall of said drum between the upper and lower ends thereof below which a pool of stock may be maintained during the operation of the drum, an inwardly extending rim on the upper end of the drum below which a second pool may be maintained, a skimming ring mounted below said rim v with a downwardly projecting flange on its outer edge submerged in said second pool, and an annular ridge submerged in said second pool between sald rib and said ring, the inner surface of the drum wall having an upwardly flaring portion between the crest of said ridge and the lower end of the skimming ring flange.

GUMAL KNOPP. 

